Custom hooks extract and share stateful logic. Here are essential patterns for building them.
useLocalStorage
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useFetch
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useDebounce
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useToggle
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useClickOutside
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useMediaQuery
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usePrevious
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useInterval
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useAsync
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useForm
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useCopyToClipboard
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Best Practices
Design:
✓ Start with 'use' prefix
✓ Return object for multiple values
✓ Use TypeScript generics
✓ Handle cleanup in useEffect
Performance:
✓ Memoize callbacks with useCallback
✓ Memoize values with useMemo
✓ Use refs for values that shouldn't trigger rerenders
✓ Return stable references
Testing:
✓ Test with renderHook
✓ Test edge cases
✓ Test cleanup
✓ Test error states
Conclusion
Custom hooks encapsulate reusable stateful logic. Start with common patterns like useLocalStorage and useFetch, then build domain-specific hooks as needed. Always handle cleanup, use TypeScript for type safety, and memoize where appropriate.